As a general matter, when a cellular wireless carrier provides subscribers with communication service, the carrier will keep track of the extent of subscriber communication, such as the number of minutes of communication or the quantity of data communicated. Maintaining good records of communication usage can facilitate numerous useful functions, including subscriber billing, cost recovery from roaming partners, and evaluation of network resources, among others.
To track communication usage, infrastructure in the carrier's network will typically monitor the extent of usage and generate and send corresponding usage-records to a usage-tracking system for processing. For instance, to track legacy telephone call activity, a switch in the carrier's network may generate a call detail record (CDR) for each call to or from a subscriber and may transmit the CDR to a usage-tracking system. Likewise, to track data communications, a packet-data gateway in the carrier's network may generate usage data records (UDRs) for data communication to or from a subscriber and may transmit the UDRs to an accounting server, which may in turn transmit the UDRs to a usage-tracking system.
For purposes of billing and cost-recovery, the usage-tracking system may sort usage-records based on whether the subscriber at issue is a home subscriber or a roaming subscriber. If the subscriber has a service account with the serving carrier and the communication occurred under that account, then the usage-tracking system would deem the subscriber to be a home subscriber, and the usage-tracking system may process the subscriber's usage-records accordingly, such as by compiling the records and billing or charging the usage to the subscriber's account with the carrier. On the other hand, if the subscriber does not have an account with the serving carrier but instead likely has an account with an affiliate carrier (e.g., a carrier with which the serving carrier has a roaming agreement), then the usage-tracking system may pass the usage-records to an inter-carrier mediation system, which would facilitate recovery of the communication charges from the subscriber's carrier.